Yes, emails are currently required on almost every site. I draw this line because BrowserID/Persona (and similar efforts) are quite special - we jump from the p

Yes, emails are currently required on almost every site. I draw this line because BrowserID/Persona (and similar efforts) are quite special - we jump from the pages to browser's chrome, making user-agent actually handle authentication. I think that the first major standard to come - that'd be embedded in the browser - could change this game rules, because it must be (well - I don't know, I just think it is) a big thing. Even users who don't care would've bought secure yet seamless authentication, neat identity management and so on. But not something after this, because the momentum would be lost and there won't be enough incentive to switch. So, the first standard must have something sensible as credential, or - I fear - it will be a long time before we can hope for any changes. Maybe I'm wrong here.